Rotor of a directly gas-cooled electrical turbomachine

ABSTRACT

The cap plate ( 1 ) has an axially recessed region ( 22 ) with a shoulder ( 23 ). The gas guiding ring half shells ( 2, 3 ) have a respective projecting rib ( 15, 16 ). A retaining ring consisting of two retaining ring halves ( 11, 12 ) abuts with its first leg ( 18 ) in the shoulder ( 23 ) and is connected by means of fillister head screws ( 24 ) to the cap plate ( 1 ). The gas guiding ring half shells ( 2, 3 ) are positioned with respect to the cap plate ( 1 ) with clearance fit ( 35, 37 ) in the radial and axial direction. The ribs ( 15, 16 ) have a spacing in the peripheral direction at the separation place ( 9, 10 ) of the gas guiding ring half shells ( 2, 3 ) in order to form gaps ( 17, 36 ). At the same location, the first leg ( 18 ) of the retaining ring halves ( 11, 12 ) is interrupted for the formation of recesses ( 20, 25 ) aligned with the gaps ( 17, 36 ). Fixing wedges ( 26 ) are inserted in the region of the gaps ( 17, 36 ) and of the recesses ( 20, 25 ) and are screwed to the cap plate ( 1 ). These fixing wedges ( 26 ) transfer the tangential forces from the gas guiding ring half shells ( 2, 3 ) to the retaining ring halves ( 11, 12 ).

TECHNICAL FIELD

[0001] The present invention relates to a rotor of a directly gas-cooledelectrical turbomachine, which rotor has at each axial end a respectivegas guiding ring consisting of two gas guiding ring half shells,respectively connected to a cap plate of the rotor. It also relates to aprocess for the assembly of such a rotor.

STATE OF THE ART

[0002] The rotor cap, particularly in rotors of a turbogenerator withdirect gas cooling, is known to undergo ovalization due to thecentrifugal force which acts on it and on the windings lyingtherebeneath. This ovalization also relates to the cap plate and the gasguiding ring. Due to the pressure difference arising at the gas guidingring half shells during operation of the turbogenerator, a known axialdisplacement results in known turbogenerators, and produces wear.Furthermore, during shaft rotation (rotational speed less than 40 rpm)of known turbogenerators, a tangential and radial movement of the gasguiding ring half shells arises, which leads to additional wear in thecap plate.

SUMMARY OF THE INVENTION

[0003] The invention thus has as its object to provide a rotor of adirectly gas-cooled turbomachine, in which axial displacements of thegas guiding ring half shells and also tangential and radial movements ofthe gas guiding ring half shells are made impossible. The rotoraccording to the invention is distinguished by fixing wedges, arespective one of which is inserted at the place of the separationbetween mutually opposing end sections of the gas guiding ring halfshells, abuts on both sides on the end region sections, and is securelyconnected to the cap plate. Moreover, the rotor has a retaining ringconsisting of two retaining ring halves, connected to the gas guidingring and likewise connected to the cap plate, in order to position thegas guiding ring axially and radially with respect to the cap plate. Therespective separation place of the gas guiding ring half shells isoffset here by at least about 90° from the respective separation placeof the retaining ring halves.

[0004] The process is characterized in that the gas guiding ring halfshells are inserted into the cap plate and pressed apart with respect tothis, then the fixing wedges are fitted into the gaps between themutually opposing end sections of the gas guiding ring half shells andare secured, the gas guiding ring half shells are released and theretaining ring halves are positioned on the gas guiding ring halfshells, and finally the retaining ring halves are screwed to the capplate.

[0005] Advantageous embodiments will become apparent from the dependentclaims. The advantages of the invention are particularly that theretaining ring halves position the gas guiding ring half shells bothaxially and also radially, and simultaneously also, by means of thefixing wedges, absorb the tangential forces when a short circuit occurs.The retaining ring halves are held in a recessed region against thecentrifugal forces. It is thus ensured that both in the stationary stateand also during shaft rotation, the gas guiding ring half shells arefixed in every direction, so that no wear arises. However, the gasguiding ring half shells can accommodate the ovalization of the capplate in operation.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The subject of the invention is described in detail hereinbelowby way of example using drawings of a mode of embodiment.

[0007]FIG. 1 shows a front view of a rotor of a turbogenerator with agas guiding ring and a retaining ring,

[0008]FIG. 2 shows a section along the line II-II of FIG. 1,

[0009]FIG. 3 shows a section along the line III-III of FIG. 1,

[0010]FIG. 4 shows a section along the line IV-IV of FIG. 1,

[0011]FIG. 5 shows a retaining ring consisting of two retaining ringhalves,

[0012]FIG. 6 shows a section along the line VI-VI of FIG. 5,

[0013]FIG. 7 is a diagrammatic illustration of a gas guiding ringconsisting of two gas guiding ring half shells, without retaining ring,

[0014]FIG. 8 shows a section along the line VIII-VIII of FIG. 5,

[0015]FIG. 9 shows a section along the line IX-IX of FIG. 5,

[0016]FIG. 10 shows a front view of a fixing wedge,

[0017]FIG. 11 shows a side view of the fixing wedge of FIG. 10.

MODES OF EMBODIMENT OF THE INVENTION

[0018] The rotor constituted according to the present invention has (atboth axial ends) a cap plate 1 and also a gas guiding ring consisting oftwo half shells 2 and 3. The gas guiding ring half shells 2 and 3contain the gas guiding blades 4. The reference numerals 5, 6, 7 and 8denote the filler pieces, known per se, between respective adjacent gasguiding blades 4. The reference numbers 9 and 10 furthermore denote theseparation places between the gas guiding ring half shells 2 and 3. Thegenerator windings 21 are furthermore drawn in in FIG. 2. A retainingring consisting of two retaining ring halves 11 and 12 can furthermorebe seen in FIGS. 1 and 2; more detail is given hereinafter regardingthis retaining ring. The separation places of these holding ring halvesare denoted by 13 and 14.

[0019] It can be seen that the separation places 9, 10 of the gasguiding ring half shells 2 and 3 are offset by 90° with respect to therespective separation places 13, 14 of the retaining ring halves 11, 12.

[0020] The gas guiding ring half shells 2, 3 each have a rib 15 or 16projecting in the radial direction. It can be seen from FIG. 7 that theribs 15, 16 have a mutual spacing at a respective separation place 9, 10of the gas guiding ring half shells 2, 3, so that gaps 17, 36 arepresent. Only the upper gap 17 is visible in FIG. 7, while the lower gap36 is covered by the gas guiding ring half shells 2, 3.

[0021]FIG. 5 shows the whole retaining ring, consisting of the tworetaining ring halves 11, 12, while FIG. 6 shows only the retaining ringhalf 12. Sections through the retaining ring half 11 are shown in FIGS.8 and 9.

[0022] The retaining ring halves 11, 12 have a L-shaped cross sectionalshape with a first and a second leg 18, 19. It can be seen from FIG. 6that the first leg 18 of the retaining ring halves 11, 12 isinterrupted, so that a recess shaped as a groove is respectively formedin the middle. The recess of the retaining ring halves 11 is denoted by25 and the recess of the retaining ring halves 12 is denoted by 20 here.

[0023] It can be seen from FIGS. 3 and 4 that the cap plate 1 has anaxially recessed region 22 running around it, so that a shoulder 23 isformed. The shoulder 23 has a radial distance from the rib 16 of the gasguiding ring half shell 3. The first leg 18 of the retaining ring halves11, 12 projects into the annular space thus formed. Only the retainingring half 11 is visible in FIGS. 3 and 4; however, the retaining ringhalf 12 has analogous insertion conditions.

[0024] The retaining ring halves 11, 12 are securely connected to thecap plate 1 by means of fillister head screws 24. The first leg 18 ofthe respective retaining ring half 11, 12 abuts laterally on the capplate 1. On the other hand, the second leg 19 of the L-shaped crosssection of the respective retaining ring half 11, 12 abuts on the sideof the rib 16 remote from the cap plate 1, i.e., on its outer side. Anaxial clearance fit 37 is then formed between the second leg 19 and therib. It is thus apparent that the respective gas guiding ring half shell2, 3 is secured against an axial displacement relative to the cap plate1.

[0025] Furthermore, the first leg 18 abuts along its outer periphery onthe shoulder 23 of the cap plate 1 and along its inner periphery on therib 15, 16. A radial clearance fit 35 is formed between the rib 15, 16and the first leg 18. Thus the respective gas guiding ring half shell 2,3 is also secured against a radial movement with respect to the capplate 1 and the respective retaining ring half 11, 12 is also securedagainst a radial movement in the cap plate 1.

[0026] As has already been mentioned, the retaining ring halves 11, 12have recesses 25, 20, which are in particular apparent from FIGS. 5 and6. These retaining ring halves 11, 12 are arranged between the gasguiding ring half shells 2, 3 and the cap plate 1, as can particularlybe seen from FIG. 2. The orientation of the retaining ring halves 11, 12and the gas guiding ring half shells 2, 3 then corresponds to theorientation of the draftsman's illustration in FIGS. 6 and 7. It followsfrom this that the recesses 25, 20 in the retaining ring halves 11, 12coincide with the gaps 17, 36 between the ribs 15, 16 of the gas guidingring half shells 2, 3.

[0027] Fixing wedges 26 are inserted into the gaps 17, 36 and therecesses 25, 20. The dimension of the height 29 of the fixing wedges 26corresponds to the dimension of the height 28 of the second leg 19 ofthe L-shaped retaining ring halves 11, 12. The dimension of the depth 27of the fixing wedges 26 corresponds to the dimension of the depth 30 ofthe first leg 18 of the retaining ring halves 11, 12. Finally, thedimension of the width 31 of the fixing wedges 26 corresponds to thewidth of the gaps 17, 36 or of the recesses 25, 20.

[0028] As already shown in FIGS. 3 and 4, the retaining ring halves 11,12 are screwed to the cap plate 1 with fillister head screws 24, withthe head of a respective fillister head screw 24 seating in therespective bore 32 of the retaining ring halves 11, 12 with the greaterdiameter, and the shaft running through the bore 33 with the smallerdiameter (FIG. 9).

[0029] In the region of the recesses 25, 20, the head of a respectivefillister head screw is likewise seated in the respective bore 32 withthe greater diameter (FIG. 8). However, the shaft of the fillister headscrew screwed to the cap plate 1 runs through the bore 34 of the fixingwedge 26 (FIGS. 10, 11). The head of the tightened fillister head screw24 is thus situated directly at the fixing wedge 26 (FIG. 4).

[0030] When assembling the rotor, the gas guiding ring half shells 2, 3are first inserted into the cap plate 1. The gas guiding ring halfshells 2, 3 are then pressed apart in the separation places 9, 10, andat the respective gaps 17, 36, the two fixing wedges 26 are fitted inand secured by means of a fillister head screw (not shown) to the capplate 1. Furthermore finally the retaining ring halves 11, 12 areconnected to the cap plate 1.

[0031] It is thus apparent that the retaining ring halves 11, 12position the gas guiding ring half shells 2, 3 axially and radially. Atthe same time, at a short circuit moment, the tangential forces areabsorbed by means of the fixing wedges 26. The retaining ring halves 11,12 are in their turn held against centrifugal force in the describedannular space in the cap plate 1. All the parts are designed with thenecessary tolerances for a stress-free retaining of the gas guiding ringhalf shells 2, 3 and in addition are treated with lubricant. It is thusensured that both in the stationary state and also during shaftrotation, the gas guiding ring half shells are secured in alldirections, so that no wear can take place. In operation, however, thegas guiding ring half shells 2, 3 can adapt to the ovalization of thetwo cap plates 1 at the two rotor ends. List of Reference Numerals 1 capplate 2 gas guiding ring half shell 3 gas guiding ring half shell 4 gasguiding blade 5 filler piece 6 filler piece 7 filler piece 8 fillerpiece 9 separation place, between 2 and 3 10 separation place, between 2and 3 11 retaining ring half 12 retaining ring half 13 separation place,between 11 and 12 14 separation place, between 11 and 12 15 rib 16 rib17 gap between 15 and 16 18 first leg of 11, 12 19 second leg of 11, 1220 recess of 11 and 12 21 generator windings 22 axially recessed area inthe cap plate 23 shoulder in the cap plate 24 fillister head screw 25recess of 11, 12 26 fixing wedge 27 depth of 26 28 height of 19 29height of 26 30 depth of 18 31 width of 26 32 bore (head portion) 33bore (shaft portion) 34 bore (shaft portion) 35 clearance fit, radial 36gap between 15 and 16 37 clearance fit, axial

1. Rotor of a directly gas-cooled electrical turbomachine, which rotorhas at each of its two axial ends a respective gas guiding ringconnected to a cap plate (1) of the rotor and consisting of two gasguiding ring half shells (2, 3) with separating places (9, 10), whereina retaining ring, consisting of two retaining ring halves (11, 12) withseparation places (13, 14) and connected to the gas guiding ring halfshells (2, 3), is securely connected to the cap plate (1), in order toposition the gas guiding ring axially and radially with respect to thecap plate (1), the respective separation place (9, 10) of the gasguiding ring half shells (2, 3) being offset by at least about 90°relative to the respective separation place (13, 14) of the retainingring halves (11, 12); ribs (15, 16) projecting, respectively in theradial direction, from the respective gas guiding ring half shells (2,3), abut laterally on the cap plate (1), and a respective fixing wedge(26) is inserted at the respective separation places (9, 10) of the gasguiding ring half shells (2, 3) in gaps (17, 36) between the ribs (15,16), abuts the retaining ring halves (11, 12) on both sides in recesses(20, 25) of the retaining ring halves (11, 12), and is securelyconnected to the cap plate (1).
 2. Rotor according to claim 1, whereinthe cap plate (1) has an axially recessed region (22) for forming ashoulder (23), the said shoulder (23) being arranged at a radialdistance from the respective rib (15, 16), so that an annular space ispresent between the shoulder (23) and the ribs (15, 16), in whichannular space a first leg (18) of the retaining ring halves (11, 12)connected to the cap plate (1) is arranged, which first legs (18) abutalong their outer periphery on the shoulder (23) of the cap plate (1)and laterally on the cap plate (1), and also have a clearance fit (35)to the rib (15, 16) along their inner periphery.
 3. Rotor according toclaim 2, wherein each retaining ring half (11, 12) has an L-shaped crosssectional shape, a second leg (19) of the L-shaped retaining ring halves(11, 12) being constituted and having a clearance fit (37) to the sideof the respective rib (15, 16) remote from the cap plate (1).
 4. Rotoraccording to one of claims 1-3, wherein the ribs (15, 16) of the gasguiding ring half shells (2, 3) have a mutual spacing at the separationplace (9, 10) in order to form a gap (17, 36), and the first leg (18)has a recess (20, 25) coinciding with the gap (17, 36); a respectivefixing wedge (26) being inserted at the gaps (17, 36) and the recesses(20, 25).
 5. Rotor according to claim 4, wherein the dimension of theheight (29) of each fixing wedge (26) corresponds identically to thedimension of the height (28) of the second leg (19) of the respectiveretaining ring half (11, 12), the dimension of the depth (27) of eachfixing wedge corresponds identically to the dimension of the depth (30)of the first leg (18), and the dimension of the width (31) of eachfixing wedge (26) corresponds to the width of the gaps (17, 36) or ofthe recesses (20, 25).
 6. Rotor according to claim 5, wherein theretaining ring halves (11, 12) and fixing wedges (26) are connected tothe cap plate (1) by means of fillister head screws (24) having a headand a shank, the head of the fillister head screw (24) being arrangedcountersunk in the second leg (19) of the respective retaining ring half(11, 12), and the shaft running through the first leg (18) or the fixingwedge (26), such that the head of the fillister head screw (24) screwedinto the cap plate (1) is supported on the first leg (18) or on therespective fixing wedge (26).
 7. Process for the assembly of the rotoraccording to claim 1, wherein the gas guiding ring half shells (2, 3)are inserted into the cap plates (1) and are pressed apart against thesame, then the fixing wedges (26) are fitted into the gaps (17, 36)between the separation places (9, 10) of the gas guiding ring halfshells (2, 3) and are secured, the gas guiding ring half shells (2, 3)are released and the retaining ring halves (11, 12) are positioned withclearance fit (35, 37) on the gas guiding ring half shells (2,3), andfinally the retaining ring halves (11, 12) are screwed to the cap plate(1).